An assessment of the impact of pollution on global cloud albedo

Increased pollution leads to increasing particulate concentrations. Since some particles nucleatedrop formation, clouds will contain, with increasing pollution, more drops per unit volume, andhence will tend to be optically thicker and more reflecting. An opposite effect is also present, inthat increasing absorption also attends increasing pollution. Measurements suggest that theformer (brightening) effect is the dominant one for global climate and that the climatic effect isquite comparable to that of increased carbon dioxide, and acts in the opposite direction.